Resin produced from still residues



PatentedNov.l18,1 941 UNITED "STATES PATENT OFFICE rial .No.

. aas m PRODUCED FROM STILL nusmus Joseph Rivkin Pa., burgh, Pa.,

assignors to The Neville Company,

a corporation of Pennsylvania and Lyle M. Geiger, Pittsburgh,

Pitts- No Drawing. Application'scptember 21,1938,

Serial No. 230,

3 Claims. (Cl. 26iL-81) This invention relates to the improvement ofresins derivable from still residues obtained in the recovery ofaromatic light oils produced in the high temperature carbonization ofcoal in.

by-product coke ovens.,, o

The aromatic light-oils present in coke oven gases are usually scrubbedout with a wash oil to produce a solution" of the light oils'which isthen distilled to obtain a mixture of light oils that is fractionated toobtain impure cuts ofthe individual oils. These cuts are then subjectedto distillation in the so-called pure stills to obtain purifiedbenzol,motor benzol, toluol, and

xylol. Before actual distillation, however, the impure cuts are treatedwith sulfuric acid to refine them, and the acid remaining in the cuts isthen neutralized, commonly with lime or soda ash, or both. .The residuesremaining in thepure stills used in the production of purified sol-jvents are commingled and are knownin the trade as pure still residues.

These residuescomprise mixtures of resins and oils in varying amountsdepending, for example, on the degree to which the solvents have beenstripped out in distillation, together with a substantial content ofmineral matter, or ash, aristhe ash content remains in it and, due toremoval of the oils, the concentration of ash becomes higher, reachingas much as 18 to 20 per cent by weight of the resin.

The resin thus recovered has some properties is highly objectionablebecause it causes the resin to have a dull appearance and a granularfracture, which thus injures its appearance and limits its use becausefor these purposes brilliant color and conchoidal fracture are desired.a The I ash is objectionable for some purposes also because it is. atleast to some extent, soluble in water and exhibits an alkalinereaction. The

I ash "is especially objectionable in the production of suchmaterials aslacquers, varnishes and the resin, for instance in aromatic solvents,show I ing largely from the neutralization step referred.

to. Some portion of the ash may appear as-calcium sulfate and thus beneutral and insoluble in water. A substantial part of the ash is,however, alkaline in character and more or less soluble in water.Although variable, the composition of pure still residues may be taken,on an average,

Pure still residues are generally disposed of by- --adding themv to pokeoven tar, or by burning them as fuel...beosuse as produced their marketa ,value, has heen insumcienti to 'iustify a y hins else, there beingknown' no profitable mode of working-them up into useful products.- j

- A method of recovering the resincontent of pure still residuesdisclosed and claimed in a copending application of WilliamH. Carmody,Se-

85,747, filed June 1'7; 1936, involves steam distillingthefstillresidues heated to at least about 250 C. to strip them of high boilingoils,

leaving the resin as a residue. This resin may other coatingcompositions because solutions of partial settling of the insolublematter, while films of the resin made from. such solutions exhibit anon-uniformand grainy surface. Similarly, solutions of the resin indrying and semidryingoils exhibit considerable insoluble matteroriginating in the ash content of the resin.

' These characteristics prohibit the use 01' this resin for manycommercial applications.

,Another objectionable characteristic of the as follows: resinproducedas described above is that it melts v f o v Per' t 35 withconsiderable foaming, and when melted the Volatile ,oil solution is ofhigh viscosity due to the increase Resinous bodies 30, x 'in internalresistance to flow caused by the finely Ash- :5 divided ash.

vantages due to the ash content of the resin are reduced or eliminated,More particularly, the

have a melting point as high as 0.; dependupon the thoroughness withwhich the oils are removed. in such production of the resin inventionaims to provide resinof the class described which possesses a glossyappearance and a conchoidal fracture, forms melts of low viscosity;solutions of which produce dried films which are smooth and clear, andin'which theash has been converted-t0 a form compatible 'with the'resinand products made therefrom so that it does not exhibit the undesirableproper- .tiesof untreated resin, Y

The invention is predicated upon our discovery that its stated objectsare attained by neutralizing the alkaline content of the ash with inorganic acidic material, more particularly those of resinous or plasticcharacteristics. We have discovered, in other words, that by treatingresin derived or producible from pure still residues with an organicacidic material the ash content is converted to a form, presumably asoap, which is fully compatible with the resinous matrix in which itremains, and is non-alkaline and insoluble in water, while the resultantresin exhibits true resin characteristics as to appearance and fractureand may be worked up into coating compositions and other products inwhich absence of deposit and production of clean, bright films is anessential property.

In the practice of th invention any organic acidic material capable ofneutralizing the alkaline ash content of the resin may be used, but foreconomic reasons the cheap materials are most, desirable, especiallysince the brown color of the resin warrants only a relatively low marketprice. Examples of these are colophony, the

copals, sandarac, and the like, or any of the fatty acid pitches such asthose derived from cottonseed, tallow, or lard. At present we prefer touse rosin, particularly wood rosin. Particularly, economy is afforded bythe acid sludge resultant from washing of the light,oils with sulfuricacid. This sludge comprises, in addition to acid, resin polymers andresin sulphonic acids capable of neutralizing the ash content of theresin contemplated, and not only is it a Waste material,

but also it originates at the source of the pure still residues, forwhich reason its use is economically desirable in the practice of theinven tion.

In the practice of the invention there is added to theresin, or materialcontaining the resin, an amount of organic acidic material sufficient toreact with the alkaline content of the ash. For most purposes and. inmost instances it is necessary to heat the mixture to efiect theashconverting reaction, and for most purposes the mixture should beheated to at least about 200 C., suitably above about 250 C. The uppertemperature limit is, of course, governed by the temperature at whichthe resin would undergo depolymerization or decomposition. We have foundthat with most of the organic acidic materials referred to specifically,suitable results are obtained by heating the mixture at about 260 to 285C.

The amount of organic acidic material will depend, of course, upon theacidity, in terms of acid number, of the material, and upon thealkalinity of the ash contained in the resin, which will vary somewhatdepending upon various factors such as the alkali used in neutralizingthe light oil, the source of the still residues, and the like. In thepractice of the invention, however, there is used sulficient organicacidic material to neutralize that portion of the ash which is alkalineand convert it to an organic soap, such as a fatty acid soap or aresinate.

There may be used resin produced in accordance with the inventiondisclosed in the aboveidentified application of William H. Carmody. Asexemplifying this, in one test a mixture of 77 parts of such resin and23 parts of cottonseed pitch washeated until completely fused and thetemperature was then raised to 260 C., the mixture being continuouslystirred. Before the melt reached260 C. considerable foaming occurred.After about one-half hour the foaming subsided and the product waspoured into a pan.

The resulting resin was hard and brittle, and

. tent.

it possessed a bright satisfactory fracture, all in contrast withuntreated resin. The product different from the original resin also inthat a solution of the treated resin in xylol yielded a much smootherand less seedy film than a similar solution of the original resin.

In another similar test a mixture of per cent by weight of resin of140-150 C. melting point and 20 per cent by weight of wood rosin of WWgrade were heated, with stirring, at 265 to 280 C. for 12 minutes. Theproduct was then poured into pans and allowed to cool. When cool itexhibited the characteristics of resin prepared in accordance with thisinvention, namely, conchoidal fracture and bright appearance, incontrast with the dull appearance and granular fracture of the untreatedresin. i

This treated resin was dissolved by heating in cold-processedsardineoil, and the solution yielded smoother and more satisfactoryfilms than the untreated resin of the same grade. Solutions of thetreated and untreated resin were also made in Stoddard solvent naphtha,using 50 per cent by weight of resin and 50 per cent by weight of thesolvent naphtha. Panels were flowed out from each solution. That madefrom the treated resin provided a satisfactory and continuousfilmshowing but a slight amount of undissolved matter. The panel preparedfrom the untreated resin yielded an unsatisfactory film containingundissolved matter thickly deposited by the solvent to yield an opaqueand very seedy film which was of no value.

Although the resin itself may be treated in accordance with theinvention, the foaming which occurs in consequence of the reaction maybe objectionable, and may, in some instances, be difficult to control.

For this reason it is preferred to treat the pure still residue toconvert the ash content prior to recovery of the resin. That is, thepure still residue is mixed with a sufficient amount of organic acidicmaterial to neutralize the alkaline ash content, the mixture is heatedto complete the reaction, and the oil is then removed by distillation toleave the resin as a residue. The melting point of the resin isdependent upon and controllable by the extent to which the oil has beenstripped out. The resin thus obtained contains the ash converted, in

accordance with the invention, to a form that is less obnoxious than inuntreated resin.

For instance, in this embodiment the pure still residue and an organicacid material such as wood rosin are charged into a still and. heatedto, for instance, 260 C., to initiate reaction. Thereafter steam ispassed through the mix to drive out the high boiling oils to the desiredex- The bulk of the distillation will occur at a temperature of about260 to 285 C., and distillation is continued until samples show theresidue in the still to be satisfactory. Resins having melting pointsfrom 10 to C. are easily obtained in this manner.

Using wood rosin we have found that with Clairton stil1 residues ofaverage composition satisfactory results are had with about 88 parts ofpure'still residues and 12 parts of wood rosin. The oil obtained in thisembodiment of the invention is apparently similar in its properties tothat obtained when the pure still residues are distilled prior toapplying the invention to the resin except that when wood rosin is usedthe oil has a piney odor.

In one test of this aspect of the invention a mixture of 60 parts ofpure still residue'and 40 parts of acid solution resulting from acidwashing of the light oils from which the pure still residues werederived was heated in a still and steam-distilled to a. stilltemperature of 280 C., removing the volatile oils. The residual, productwas a hard, brittle resin which diflered from that obtained by simpledistillation of the same residues in that it had a brighter, moretypically resinous fracture. It possessed also improved solubility inaromatic solvents, as was shown by making 25 per cent solutions in xylolof the treated resin and untreated resin produced from,

the same residues by distillation without the use of acid sludge. Thetwo solutions were allowed to stand over night, and at least.twice asmuch sediment settled from the solution of untreated I resin as from thetreated resin.

According to the provisions of the patent manner of practicing ourinvention, and have described what we now consider to be its bestembodiment. However, we desire to have it understood that, within thescope of the appended claims, the invention may be practiced otherwisethan as specifically described.

- of coal which comprises neutralizing the alkaline ash content of theresin materialwith rosin at an" elevated temperature, and recoveringresin containing the reacted ash.

2. That method of producing resins of improved character frorn'purestill residues derived from' fractionation of light oil produced inby-produc't coking of coal which comprises neutralizing the alkaline ashcontent of the pure still residues at an elevated temperature with rosinand steam distilling the mixture to remove oil therefrom and, produceresin of desired melting point containing the reacted ash content ofsaid residues.

3. As a new article of manufacture, a resin produced by distillation ofoil from pure still resiul I m fr ct nat i statutes, we have explainedthe principle and 20 dues res tant to a 10 Ion of lght on produced inby-product coking of coal, the resin having at least a portion of itsash content in the form of a resinate; being bright, glossy and brown incolor, and having a brilliant conchoidal fracture.

' JOSEPH RIVKDL' LYLE M. GEIGER.

